The present invention relates to a method for separating web rolls on a conveyor from each other.
The invention also relates to a roll conveyor suited for implementing the method.
Web rolls manufactured on a paper or paperboard machine are slit at a slitter-winder from a wide machine roll into rolls of narrower width according to customer order. Slitter-winders fall into two main types: shaft-supported slitter-winders, in which the slit rolls are delivered from the slitter in two different sets to both sides of the winder, and surface-driven slitter-winders, in which the slit rolls are delivered as a complete set. Since surface-driven belt-supported slitter-winders are based on the same principle as surface-driven roller-supported slitter-winders, in a general sense it is appropriate in this context to assign the term “surface driven slitter-winder” to any winder-slitter capable of delivering the rolls as a complete set.
Rolls manufactured on a surface-driven slitter-winder must be separated from each other for such reasons as, e.g., quality checks, before the slit rolls can be transferred further to a labeling and packaging station. Conventionally, the rolls of a roll set delivered by the slitter-winder are separated from each other at a transition point between two roll conveyor sections. When the separation point between the first and second roll of a roll set coincides with the transition point between the conveyor sections, the first conveyor is stopped, whereby the first roll of the set continues its travel on the second conveyor, while the other rolls of the set remain on the first conveyor. Subsequently, the separation point between the second and third roll is driven to the transition point between the conveyor sections, whereupon the first conveyor is stopped causing the second roll to continue its travel on the second conveyor, while the other rolls of the set remain on the first conveyor. The same sequence is repeated until all of the rolls of the set are separated from each other.
The rolls of a set received from a slitter-winder may stay adhered to each other due to different reasons: the core ends are not flush with the web roll ends, the sheet edges of the rolls are slit uneven leaving them interleaved with each other or slitting has been started too late whereby the core still has some layers unslit. If the rolls adhere to each other, problems may occur at the transition point between the conveyors in the case that the rolls fail to separate. To avoid such complications, full separation of rolls must be checked in a set received from a surface-driven slitter-winder. While checking the separation of rolls in a set may occur at any place along the transfer of the roll set, generally the check is performed through arching the roll set by way of elevating the middle rolls of the roll set upward so much that the roll ends separate from each other leaving a gap therebetween. At this moment, the operator checks visually that all rolls are separated from each other and, if necessary, uses a wedge to force apart any rolls adhering to each other. Although modern slitter-winders are extensively automated, monitoring the rolls in a roll set and separation of the rolls from each other in operation is still being performed manually. These worksteps prevent running a slitter-winder with lesser manpower. In addition to being monotonous and tedious, such operator tasks may be even hazardous if carried out counter to instructions or by negligence. Sufficient time must also be reserved for the operator's actions to permit his checks on the roll set to be performed safely. Due to the manual separation of rolls, the operation of the slitter-winder and the roll conveyor system is slowed down.